A portion of the disclosure of this patent document contains material, which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.
This present invention relates to the interworking of computer networks. Specifically, the invention relates to a proxy that groups Media Gateways.
Internet telephony encompasses a number of technologies for the transport of voice traffic over Internet Protocol (IP) networks. IP telephony can be divided into a media plane, a signaling plane, and call control plane. The media plane provides functionality required for media transport, such as packetization of voice data, packet delivery, and media playout at the destination. The signaling and call control plane provides functionality required to set up, tear down, and manage calls.
One aspect of Internet Telephony is the interworking of the IP network with the existing Public Switched Telephone Network (PSTN). In the context of PSTN interworking, the media and signaling planes include expanded functionality in order to connect the different network types. Thus, the media plane incorporates components which translate and map the voice data between a circuit switched network and an IP (packet) network, enabling it to act as a gateway between the two different means of media transport. Similarly, the signaling and call control plane incorporates components which translate and map signaling and call control protocols between PSTN and IP networks, in order to set up, tear down, and manage calls which traverse both types of network.
The development of common protocols and architectures for the PSTN interworking function is a major focus of several standards bodies, including the Internet Engineering Task Force (IETF) and International Telecommunication Union (ITU). While this is a large task requiring the resolution of many technical issues, one general architecture that has emerged in which the media plane and signaling and call control plane are viewed as distinct elements. The media component is referred to as a Media Gateway (MG). The signaling and call control component is further divided into two elements. A Media Gateway Controller (MGC) both controls the MG remotely, and handles IP-side signaling and call control with peer elements on the IP network. In addition, a Signaling Gateway provides the mapping and translation between the PSTN and IP signaling and call control protocols. One problem is that the general architecture does not necessarily specify the implementation of such components. For example, the Signaling Gateway and the MGC could be implemented as a single, integrated component.
The MGC and MG are configured in a master (MGC)xe2x80x94slave (MG) relationship, and multiple MGs may be under the control of a single MGC. Regardless of the number of MGs under a given MGC, or the actual physical implementation of the MG, the MGC views each MG under its control as a distinct entity with which it communicates via a well-specified software interface. The various protocols that are being developed define standard sets of media processing capabilities, as well as the MGC-MG interface. Current protocols under development within the IETF include the Media Gateway Control (MEGACO) and Media Gateway Control Protocol (MGCP). Within the ITU, H.248 is the standard for the interface.
Because the MGC""s only view of the MG is via the standard interface, it has no visibility into how the actual media resources are configured behind the interface in order to support the capabilities required by the interface. The media resources may be part of an integrated hardware platform (e.g., DSPs, controlling processors, and buses), or alternatively, a collection of distinct platforms, coordinated and managed by software which presents the standard MG interface to the MGC.
Thus, it is desirable to provide a virtual Media Gateway (MG) composed of multiple standalone media gateways. It would also be desirable to allow an outside entity, for example, a Media Gateway Controller (MGC), to transmit messages to a virtual Media Gateway and receive messages from a virtual Media Gateway and allow the outside entity to view the virtual Media Gateway as a single Media Gateway.
The invention relates to a virtual Media Gateway (MG) including multiple standalone media gateways. The virtual Media Gateway is a grouping, which contains multiple individual Media Gateways. Specifically, the invention relates to a Media Gateway proxy that allows an outside entity, for example, a Media Gateway Controller (MGC), to transmit messages to a virtual Media Gateway and receive messages from a virtual Media Gateway. The Media Gateway proxy allows the outside entity to view the virtual Media Gateway as a single Media Gateway.
In one embodiment of the present invention, an external Media Gateway Controller is coupled to a Media Gateway proxy via a standard software interface (e.g., MEGACO). The proxy is coupled to a plurality of Media Gateways. The Media Gateways are organized into groups. Each group is a virtual Media Gateway.
The external MGC transmits messages to the Media Gateway proxy. In one embodiment, the Media Gateway proxy comprises a frontend, middleware, and an internal MGC. The messages contain a plurality of sub-commands, attributes, and a virtual destination address. The virtual destination address is an address of a virtual Media Gateway. Each attribute relates to a particular physical Media Gateway.
The Media Gateway proxy receives the message. In one embodiment, for each sub-command, the Media Gateway proxy extracts the sub-command and the attributes associated with the sub-command. The proxy then determines the destination physical IP address (of the destination MG) for the command. In another aspect of the present invention, the proxy receives replies from the MGs. The proxy maintains a table of activity with respect to the commands it receives. The proxy maintains a record of the messages received from the MGC. When all reply messages (associated with a particular message from the MGC) have been received, the proxy aggregates the responses and sends a reply to the external MGC.
The foregoing and the other features and advantages of an illustrative embodiment of the present invention will be more readily apparent from the following detailed description which proceeds with reference to the accompanying drawings.